Scientists predict the comet will hurtle past the sun in December and keep going until it's back in interstellar space. It should be visible with professional telescopes well into next year. Its nucleus is estimated between 1.2 miles and 10 miles across (2 kilometers and 16 kilometers).

Officially known as C/2019 Q4, the comet was discovered two weeks ago by an amateur astronomer at an observatory on the Crimean Peninsula. In 2017, a telescope in Hawaii spied our first known interstellar visitor.

With another so soon, these interstellar passers-by could be more common than thought.

"We are now working on getting more observations of this unusual object," Marco Micheli of ESA's Near-Earth Object Coordination Center said in a statement. "We need to wait a few days to really pin down its origin with observations that will either prove the current thesis that it is interstellar, or perhaps drastically change our understanding."

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